This invention relates to protective devices and in particular to a protective device for instruments mounted on an instrument panel. More specifically, but without restriction to the particular use which is shown and described, this invention relates to a protective cover and lock means for the cover for protecting the radio and navigational instruments mounted on the instrument panel of an aircraft against theft.
Most privately owned light aircraft are provided with navigational instruments and radio equipment that are mounted for easy installation or removal for repair or replacement from the front of an instrument panel mounted within the airplane cockpit. Furthermore, most light aircraft are provided with cable operated controls including ailerons and elevators connected to a control column extending from the instrument panel which is turned by a wheel or a yoke. The elevators during flight are positioned by pushing foward or pulling back the control column in its longitudinal direction, and the ailerons are positioned by rotating the wheel.
Often such aircraft are not hangared, but merely tied down outside in a remote location on an airfield when not in use. When tied down in this manner, many small aircraft are provided with a control lock or lock pin under or near the instrument panel that drops through the control column to lock it into position to prevent control surface movements and resultant damage thereto due to wind. Such small aircraft are not usually so constructed that the instrment panel thereof is contained within an enclosure or cockpit which can be locked against the entry therein of unauthorized persons. Accordingly, the removal and theft of radio and navigational equipment and instrumentation, and also of the control lock and the aircraft itself, has become a matter of major concern to the owners of such small aircraft.
A number of devices have been patented which are directed toward overcoming the problems briefly outlined above. The problem of aircraft theft has been addressed by U.S. Pat. No. 3,898,823, issued to Russel S. Ludeman, Aug. 12, 1975 which discloses a device for locking the controls of an aircraft that includes brackets secured to the pedals and control column wheel interconnected by a tubular housing enclosing a piston like spring device which resiliently locks the wheel and control column against movement when parked, so as to prevent authorized flight of the aircraft. It does not, however, offer any means to cover and prevent theft of the instruments from the instrument panel.
The problem of instrumentation theft has been addressed by U.S. Pat. No. 3,699,787, issued to Ronald F. Corrado, Oct. 24, 1972 which discloses a hollow cover which is mounted over a control column and directly in front of the instrument panel. The cover is locked in place by a tumbler lock which cooperates with a locking device fixed in the instrument panel. While this patent offers protection against theft of the instruments, the practice thereof necessitates the drilling of holes in the instrument panel for the insertion of the locking device. Furthermore, it does not prevent a thief from manipulating the control shaft and connected control wheel to fly the plane away.
Both the aforementioned problems have been addressed by U.S. Pat. No. 4,228,974, issued to August B. Yates, Oct. 21, 1980 which discloses a cover plate mounted immediately adjacent the instrument panel by means of upper and lower clamping blocks secured about the control column in such a manner as to prevent unauthorized movements of the column and access to the instruments on the panel. While such devices have proven successful in the past, the rigid clamps holding the protective panel to the control column causes serious damage thereto should an unauthorized person attempt to pry the protective panel away from the instrument panel.
The foregoing illustrates limitations of the known prior art. Thus, it is apparent that it would be advantageous to provide an alternative to the prior art.